I'm conflicted on this one. In some ways, this is a very good movie and in some ways it is not a good movie. It is very well acted. It is almost a given that Gyllenhall is going to give a superior performance. He's one of Hollywood's best. The rest of the cast is quite good too except for Russell Peters. Fortunately, his part is very small. The one that really surprised me though was Jeffrey Wright. His performance of a socially awkward scientific genius was, well, genius.
The story line is also a very good one. It's sort of a Groundhog Day meets Quantum Leap type of thing. The problem is that they do not let the audience in on any of the secrets to the program until halfway through the movie (I checked my watch because it was that confusing for that long). All of Gyllenhall's behaviour is explained eventually. But it drags on a little too long to hold the viewer's interest.
The continuity is also very full of holes. With a movie like this, I'm willing to give the film makers a bit of slack because the whole thing is quite unrealistic. But, given the parameters of the source code program set out by the Rutledge character, what happens to the characters is outside of the realm of their own reality. If you do watch it, that sentence should make sense. (I always try to give as full a review as possible without spoiling the movie.) That poor continuity leads to the ending. I won't give it away but I will say that it is a cop out that does not fit with the theme of the rest of the film.
The bottom line is that this film is very well acted but that's about it. It is a shallow movie that tries to find some depth and is not able to do so. Don't bother seeing it.